SU910607A1 - Process for isolating diacetone acrylamide - Google Patents

Description

I

The invention relates to an improvement in the process for the isolation of diacetone acrylamide from the reaction mass obtained by reacting acetone with acrylic acid nitrile in the presence of sulfuric acid. Diacetonacrylamide is used in the composition of lubricating compositions, emulsions for processing wood and leather, in the production of plastics, dyes, resistant to light, as well as a substitute for gelatin in the photo industry.

A known method for producing diacetone acrylamide by the interaction of acetone and acrylic acid nitrile in the presence of sulfuric acid at 0-70 ° C. In order to isolate the desired product, the reaction mass is diluted with water, neutralized with sodium or potassium hydroxide, extracted with diacetone acrylamide and water-immiscible solvent, the resulting layers are separated and the desired product is distilled by distillation P.

This method is characterized by a low yield of the target product (.12% of theory), the formation of a significant amount of by-products of phoron, 1-forone, resin products of deeper condensation of acetone, which are difficult to separate from diacetone acrylamide even with repeated recrystallization. In addition, the neutralization of the reaction mixture with metal hydroxides promotes further condensation of acetone conversion products to tar. The process is also characterized by a large amount of wastewater generated

IS when the reaction mass is diluted with water and neutralized with aqueous solutions of alkali metal hydroxides.

The purpose of the invention is to increase the yield of the target product and increase its quality.

The goal is achieved by the fact that during the isolation of diacetone3

acrylamide from the reaction mass obtained by reacting acetone with acrylic acid nitrile, neutralizing is carried out with 20-25 wt.H aqueous ammonia solution, separating the aqueous layer from the organic and the latter is treated with water at and the weight ratio of the organic layer and water is 1: 3.0, 3, 5, after which the extraction of the target product is carried out.

Neutralization is carried out with simultaneous purging of gaseous ammonia through the reaction mass.

The method is carried out as follows.

Diacetone acrylamide is obtained at a temperature of 55-57 ° C, a molar ratio of acrylic acid nitrile: acetone: sulfuric acid, equal to 1: 2.12, 3: 2, 8, the concentration of the starting sulfuric acid (oil, the reaction time k-k, S h

Neutralization of the reaction mass is carried out at 25 ° C with 20-25% by weight of aqueous ammonia solution to pH. The process can be carried out with the simultaneous introduction of gaseous ammonia, which reduces the solubility of unsaturated amides in the resulting saturated solution of ammonium sulfate to a minimum.

The upper hydrocarbon layer is separated from the water and then, with the aim of the most complete separation of diacetone acrylamide from the by-products (oxides of methyl, phoron, i-phoron, resins), the latter is washed with water from the organic layer at a temperature and a ratio of 5 . The recovered resins are sent for fractionation and used as a solvent. The degree of extraction of the desired product after neutralization and washing is 90-95 wt. After washing the diacetone acrylamide from the aqueous layer, it is extracted with an organic solvent which is not miscible with water (benzene, toluene, chloroform, ethylene trichloride, and the excess is distilled off. The diaceton acrylamide precipitates, which is filtered and dried, it can be used without further purification. in recycling for washing. Acrylamide as it accumulates in

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the aqueous layer is sent to polymerize it in the form of an aqueous solution.

Example 1. To 70 ml of 9b weight. The% i-sulfuric acid is added with 5 stirring a mixture of 32 ml of nitrdyl acrylic acid and 35 ml of acetone at 50 ° C for 30 minutes, after which the stirring is continued for another 4 hours at 60 ° C. 227.1 g of reaction mass are obtained.

containing 31.15 unsaturated amides (diacetone acrylamide 25, acrylamide 5, b1), determined chromatographically. Conversion of nitrile is, the yield of diacetone acrylamide per acrylic acid nitrile is 65.11 wt.%, Acryl amide is 1.3 wt. The reaction mass (111.8 g) is neutralized with 25% by weight.

20 ammonia solution to pH 7.0 at a temperature and get 41.52 g of the organic layer composition,%: Diacetonacrylamide 62.37, acrylamide 13.60-, resin 11.68-, mesityle oxide

25, 33-, phoron 3.77; water 6.09.

The degree of extraction of diacetone acrylamide during neutralization is 90%. Washing it from the organic layer was carried out 138 ml of water

30 at a weight ratio of organic layer: water, equal to 1: 3.3 and a temperature of 45C. The composition of the aqueous layer obtained after washing,%: diacetone acrylamide, 13, acrylamide 3.3, mesityl oxide 0.67, phoron 0.08, water 81.77. The degree of washing of diacetone acrylamide with water is 95.2. The monomer is extracted from the aqueous layer 132, ml of chloroform at 25 ° C.

jj The content of diacetone acrylamide in chloroform extract 10.52, acrylamide 0.05%. The degree of extraction of diacetone acrylamide by extraction with chloroform 9b, 5%. After distilling off the extractant, the mother liquor at

 after cooling it crystallizes, the precipitated crystals are dried and obtain 23.8 g of the finished product. The content,%, of the main substance 98.5, acrylamide 0.5 mesityl oxide and phoron 1.01.

Example 2. The reaction mass (120 g), prepared analogously to example 1, was neutralized with a 20 wt.% Ammonia solution to a pH of 8 (gaseous ammonia was added to achieve a given pH b value) and 0.5 g of an organic layer containing 60 , wt.% diacetoneacrylamide. The degree of extraction of the latter upon neutralization is 79.8 May.; .. The washing of diacetone acrylamide from the organic layer is carried out with 135 ml of water at a weight ratio of organic layer: water equal to 1: 3.3 and temperature. The degree of washing of diacetone acrylamide is 96.6 wt. .. The monomer is extracted from the aqueous layer with 135 ml of chloroform at. After the extractant has been distilled off, the mother liquor crystallizes upon cooling, the precipitated crystals are dried and 22.0 g of the final product containing 98.5% by weight of the basic substance are obtained. Example 3 The reaction mass (120 g), obtained as in Example 1, is neutralized with a 25% w / w ammonia solution to a pH of 7.5 at 25 ° C. Obtain +2.5 g of the organic layer. The degree of extraction of diacetone acrylamide at neutralization is 90 May. The last of the organic layer is washed at 50 ° C 1 "9.1 ml of water

when the weight ratio of the organic layer: water 1: 3,5. The degree of washing diacetonacrylamide 95 wt .. Monomer is extracted from the aqueous layer with 35 ml of chloroform at. After the extractant has been distilled off, the mother liquor is at oh0, 57; Phoron 1.18. The output of diacetoneacrylamide with a selection of 51.9.

The table shows the elementary composition and indicators of diacetonacrylamide, obtained by the proposed method and the prototype. After crystallization, the crystals are dried, and 23 g of the finished product with the content of the basic substance are obtained. 97.5 wt.%. Example (prototype). 111.8 g of the reaction mass obtained in example 1 was poured into 335, + g of ice and neutralized with 53, 7 ml of 20 solution of potassium hydroxide to pH 7 at 25-30 C. Obtain 80b, 1 g of aqueous layer composition,%: diacetone acrylamide 3 ,, acrylamide 0,78-, resin 0,6. Diacetone acrylamide is extracted from the aqueous layer with 299.7 ml of benzene at 2530 ° C. Receive 309.7 g of benzene extract of the following composition,%: diacetone acrylamide 4.79-, acrylamide 0.3, resin 0.79; mesityl oxide 0.6-, phoron 0.7. After distilling off the extractant, the resulting melt of diacetone acrylamide is cooled, the precipitated crystals are dried and obtain 19.63 g of the finished product. Content, /, of the main substance 81 ,, acrylamide 6.38-, resins 10.25; oxides of methyl

Claims (2)

Claim 1. The method of separation of diacetone acrylamide from the reaction mass obtained by the interaction of acetone with acrylic acid nitrile in the presence of sulfuric acid, comprising neutralizing the reaction mass and extracting the target product with an organic solvent, characterized in that, in order to increase the yield of the target product and improve its quality, neutralization carry out 20-25 wt.% - nym VNIIPI Order 1019/24 with an aqueous solution of ammonia, the organic layer is separated and treated with water at 40-45 ° С and a weight ratio of ^{45 of the} organic layer and water equal to 1: 3.0-3.5, and the target product is extracted. 2. The method of pop. 1, characterized in that the neutralization of 50 is carried out while passing gaseous ammonia.